What the heart is made of: Heart muscle tissue, also called cardiac muscle tissue. What makes the heart beat: Electrical signals. Average resting heart rate: 60 to 100 beats per minute (in adults) ...

Scar tissue in the heart was associated with abnormal heart rhythms among healthy, long-time male endurance athletes age 50 ...

I believe that cardiac tests such as the stress echocardiography, in which an ultrasound is done after exercise, or the stress thallium, in which a nuclear medicine is injected into the bloodstream ...

Extreme emotional stress can cause a medical condition called broken heart syndrome. For decades, doctors thought it should mainly concern women — but that’s changing.